Key area 3 – Therapeutic Uses of Cells National 4 Cell Biology

Uses of cells Insulin Production

By the end of today you will be able to: Explain that chromosomes in bacteria are ring shaped and there are other rings of DNA called plasmids. Explain that genes can be transferred from one living organism to another allowing bacteria to make new substances. State the advantages and disadvantages of genetic engineering.

Structure of a typical bacterial cell Here you can see that bacterial cells have some of the structures we have already seen in plant and animal cells. These details can only be seen under electron microscope (a very powerful microscope).

Structure of a typical bacteria cell membrane cell wall plasmid (additional DNA) Copy the diagram into the space in your booklet. cytoplasm main DNA ring (single chromosome) flagellum for movement (not always present) The DNA in bacteria is not in a proper nucleus. Instead it consists of a main ring or coil of DNA. In addition to this, there are other smaller rings of DNA called plasmids. Plasmids are involved in bacterial reproduction. Answer the questions under the diagram.

Insulin Some people need to take insulin every day of their lives. What are these people suffering from? DIABETES Diabetes is a condition where the person’s body is unable to control their blood sugar levels properly. This is caused by their body failing to produce enough insulin.

Taking insulin Most diabetics need to take insulin daily. This is usually done by injection. Some diabetics have an insulin pump fitted which automatically injects the right amount of insulin when their blood sugar level is too high. As the human population is increasing, there are more and more people who are diabetic, so more and more insulin is needed.

Genes and genetic engineering Every cell of every living thing contains genes. Genes control features and characteristics - a set of genes is like a set of plans for a living thing. Scientists can transfer genes from one living thing to another. This is called “genetic engineering”. It is possible to genetically engineer bacteria to get them to make products they couldn’t make before. Video clip - Genetic engineering

Let’s be genetic engineers! (1) Bacterial cell - doesn’t produce insulin. Genetic material (plasmid) Bacterial cell (3) Seal human gene into bacterial plasmid. (2) Insert gene for human insulin into bacterial plasmid. Human gene for insulin (4) “Engineered” bacteria will multiply and produce insulin, which can be purified and sold.

Making useful products by genetic engineering Insulin for diabetics is now made using genetic engineering. Before genetic engineering was available, diabetics were given animal insulin extracted from the pancreas of a pig. Some people were allergic to this insulin. Vegetarians did not want to use it because it came from dead animals. Genetic engineering has solved all these problems.

The pigs might be happy too!

Making useful products by genetic engineering Other useful products made in the same way include: -Factor VIII (Factor 8) – used to treat people suffering from a blood disorder called haemophilia. - Human growth hormone – used to promote growth in children who do not grow properly.

Advantages and disadvantages of genetic engineering Fast production Unlimited quantity can be produced Makes a human product instead of an animal product so avoids allergies Disadvantages Expensive Some people think it is unnatural

Stem Cells

Learning Intentions Describe what a stem cell is State how we use stem cells Discuss the dilemmas with stem cell research and genetic engineering What are stem cells? - video clip

What are stem cells? A stem cell is a body cell that can develop into any type of cell. Stem cells can divide repeatedly to form new cells. We all have stem cells in our bodies. They are in many places, but the most useful ones are found in our bone marrow, blood and fatty tissues. Other places scientists can get stem cells from include embryos, umbilical cords and placentas.

Why are stem cells important? Scientists look closely at all the genes in these cells to try and understand why we become ill. Stem cells can be used to help treat diseases, conditions and disabilities.

Using stem cells in the treatment of leukemia (a form of cancer)

Dilemma! Vote with your feet! The following slides contain dilemmas associated with genetic engineering and stem cell research. Watch the video clip and then think about the dilemma shown on the slide. If you agree with the dilemma – go to the left side of the class. If you disagree with the dilemma – go to the right side of the class. If you don’t know stand in the middle.

Video clips Dilemma 1 Therapeutic stem cells Dilemma 2 Designer babies 1 Designer babies 2 Dilemma 3 Cloning The first human clone? Dilemma 4 Saviour siblings

Dilemma 1 Scientists believe they can come up with a cure for cancer. However their research requires using stem cells from human embryos. Should scientists be allowed to take an unborn child's life for research purposes?

Dilemma 2 Scientists have discovered the gene that cause a hereditary disease which leaves victims in pain throughout their short life. Genetic engineering means that parents can choose the genetic make up of their child before they are conceived. Should parents be allowed to have designer babies, so they can choose their genetic make up?

Dilemma 3 Cloning intelligent scientists (like Einstein!) might lead to improved scientific research and make the other scientists work better (two heads are better than one?). A cure for cancer may come sooner if this were the case. Should human cloning be allowed?

Dilemma 4 Carrie is 5 and has a medical condition which means that she cannot walk very well, is in pain and is so tired all the time that it is hard for her to attend school or lead a normal life. Carrie’s Mum and Dad know that a donation of bone marrow from a close relative could help her. Nobody in the family is a close enough match. They have decided to have another child by selecting an embryo which is a match for Carrie. Should ‘saviour siblings’ be allowed?

Who are you most likely to support? Why? Meet Maggie and Jean…. Who are you most likely to support? Why? Jean can’t have children. She believes that some peoples fate is to adopt the children who are unwanted and provide them with a loving home because everyone deserves a loving home. Jean is a campaigner, she devotes her life to campaigning against abortion. She believes children who are unwanted have the right to live so people who want children can adopt them. Jean is also against IVF as she believes that since it has become more advanced and more common, more people choose IVF over adoption because they prefer to have their “own” child, leading to a greater number of children needing adopted. Maggie can’t have children. After years of no success she is finally about undertake IVF. Maggie hasn’t considered adoption because she believes that the bond with your child comes from the development in the womb, birth and bonding with a newborn baby.